employee from 01.01.2001 to 01.01.2005
Tinsukia college (PhysicsAssistant Professor)
employee from 01.01.2008 to 01.01.1922
Assam, India
Assam, India
Assam, India
In this paper, we present a quiet day empirical model of electron density (Ne) for the Indian equatorial zone at an altitude of 500 km. The model is applicable to all levels of solar activity and is based on the observation that the electron density in the F-region of the Indian zone is correlated with the F10.7 cm solar flux at each local time and in every month. Using this characteristic, we describe the model for electron density. In this model, we have used the least square fit and the polynomial fit. The electron density measured by the Retarding Potential Analyzer (RPA) on board the SROSS C2 satellite from 1995 to 2000 and FORMOSAT-1 (ROCSAT-1) satellite, operated by the National Space Organization (NSPO, now the Taiwan Space Agency (TASA)) of the Republic of China (Taiwan), from 1999 to 2004 is used to derive the relationship between Ne and F10.7. The average altitudes of SROSS-C2 and FORMOSAT-1 are 500 km and 600 km respectively. Due to this height difference, the observed data obtained by FORMOSAT-1 is normalized to match the SROSS-C2 data. The model is compared with the observations and is found to be in good agreement with them. It is applicable to quiet (Ap<15) conditions and is limited to a fixed altitude of 500 km within the latitude range of 10° S to 10° N around the 75° E meridian.
equatorial ionosphere, modeling, solar activity cycle, mathematical and numerical techniques
1. Balan N., Bailey G.J., Jayachandran B. Ionospheric evidence for a non-linear relationship between the solar EUV and 10.7 cm fluxes during an intense solar cycle. Planet. Space Sci. 1993, vol. 41, pp. 141-145. DOI:https://doi.org/10.1016/0032-0633(93)90043-2.
2. Balan N., Bailey G.J., Jenkins B., Rao P.B., Moffett R.J. Variations of ionospheric ionization and related solar fluxes during an intense solar cycle. J. Geophys. Res. 1994, vol. 99, pp. 2243-2253. DOI:https://doi.org/10.1029/93JA02099.
3. Bhuyan P.K., Baruah S. A regional mapping of the foF2 over India as an additional input to IRI. Adv. Space Res. 1996, vol. 18, no. 6, pp. 205-208. DOI:https://doi.org/10.1016/0273-1177(95)00924-8.
4. Bhuyan P.K., Chamua M. An empirical model of electron temperature in the Indian topside ionosphere for solar minimum based on SROSS C2 RPA data. Adv. Space Res. 2006, vol. 37, pp. 897-902. DOI:https://doi.org/10.1016/j.asr.2005.09.016.
5. Bhuyan P.K., Tyagi T.R., Singh L., Somayajulu Y.V. Ionospheric electron content measurements at a northern low midlatitude station through half a solar cycle. J. Radio and Space Phys. 1983, vol. 12, pp. 84-93.
6. Bhuyan P.K., Chamua M., Bhuyan K., Subrahmanyam P., Garg S.C. Diurnal, seasonal and latitudinal variation of electron density in the topside F-region of the Indian zone ionosphere at solar minimum and comparison with the IRI. J. Atmos. Solar-Terr. Phys. 2003, vol. 65, iss.3, pp. 359-368. DOI:https://doi.org/10.1016/S1364-6826(02)00294-8.
7. Bilitza D. International Reference Ionosphere. Rep. NSSDC/WDC-R&S 90-22. World Data for Rockets and Satellites. National Space Science Data Centre. Greenbelt, Md. 1990.
8. Bilitza D. International Reference Ionosphere 2000. Radio Sci. 2001, vol. 36, iss. 2, pp. 261-275. DOI:https://doi.org/10.1029/2000 RS002432.
9. Bilitza D. Ionospheric models for radio propagation studies. Rev. Radio Sci. 1999-2002. edited by W.R. Stone, IEEE and Wiley. 2002, pp. 625-679.
10. Holt J.M., Zhang S.-R., Buonsanto M.J. Regional and local ionospheric models based on Millstone Hill incoherent scatter radar data. Geophys. Res. Lett. 2002, vol. 29, no. 8. DOI:https://doi.org/10.1029/2002GL014678.
11. Jain S., Vijay S.K., Gwal A.K. An empirical model for IEC over Lunping. Adv. Space Res. 1996, vol. 18, no. 6, pp. 263-266. DOI:https://doi.org/10.1016/0273-1177(95)00935-3.
12. Kane K.P. Solar cycle variation of foF2. J. Atmos. Terr. Phys. 1992, vol. 54, pp. 1201-1218. DOI:https://doi.org/10.1016/0021-9169(92)90145-B.
13. Lakshmi D.R., Reddy B.M., Dabas R.S. On the possible use of recent EUV data for ionospheric predictions. J. Atmos. Terr. Phys. 1988, vol. 50, no. 3, pp. 207-213. DOI:https://doi.org/10.1016/0021-9169(88)90069-4.
14. Leitinger R., Zhang M.L., Radicella S.M. An improved bottomside for the ionospheric electron density model NeQuick. Ann. Geophys. 2005, vol. 48, no. 3, pp. 525-534. DOI:https://doi.org/10.4401/ag-3217.
15. Liu C., Zhang M.-L., Wan W., Liu L., Ning B. Modeling M (3000) F2 based on empirical orthogonal function analysis method. Radio Sci. 2008, vol. 43, RS1003. DOI: 10.1029/ 2007RS003694.
16. Oyama K.-I., Marinov P., Kutiev I., Watanabe S. Low latitude model of Te at 600 km based on Hinotori satellite data. Adv. Space Res. 2004, vol. 34, pp. 2004-2009. DOI: 10.1016/ j.asr.2004.07.013.
17. Radicella S.M., Zhang M.L., The improved DGR analytical model of electron density height profile and total electron content in the ionosphere. Ann. Geophys. 1995, vol. 38 (1), pp. 35-41. DOI:https://doi.org/10.4401/ag-4130.
18. Radicella S.M., Leitinger R. The evolution of the DGR approach to model electron density profiles. Adv. Space Res. 2001, vol. 27, no. 1, pp. 35-40. DOI:https://doi.org/10.1016/S0273-1177(00)00138-1.
19. Rishbeth H. Day-to-day ionospheric variations in a period of high solar activity. J. Atmos. Terr. Phys. 1993, vol. 55,iss. 2, pp. 165-171. DOI:https://doi.org/10.1016/0021-9169(93)90121-E.
20. Titheridge J.E. The electron content of the southern midlatitude ionosphere, 1965-1971. J. Atmos. Terr. Phys. 1978, vol. 35, iss. 5, pp. 981-1001. DOI:https://doi.org/10.1016/0021-9169(73)90077-9.
21. Unnikrishnan K., Nair R.B., Venugopal C. Harmonic analysis and an empirical model for TEC over Palehua. J. Atmos. Solar-Terr. Phys. 2002, vol. 64, no. 17, pp. 1833-1840. DOI:https://doi.org/10.1016/S1364-6826(02)00187-6.
22. Zhang S.-R., Holt J.M., Zalucha A.M. Midlatitude ionospheric plasma temperature climatology and empirical model based on Saint Santin incoherent scatter radar data from 1966 to 1987. J. Geophys. Res. Lett. 2004, vol. 109, A11311. DOI: 10.1029/ 2004JA010709.
23. Zhang S.-R., John M.H., Bilitza D.K., Eyken T.V., Mc Geady M., Amory-Mazaudier C., Fukao S., Sulzer M. Multiple-site comparisons between models of incoherent scatter radar and IRI. Adv. Space Res. 2007, vol. 39, no. 5, pp. 910-917. DOI:https://doi.org/10.1016/j.asr.2006.05.027.
